/*
 *    This program is free software; you can redistribute it and/or modify
 *    it under the terms of the GNU General Public License as published by
 *    the Free Software Foundation; either version 2 of the License, or
 *    (at your option) any later version.
 *
 *    This program is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    GNU General Public License for more details.
 *
 *    You should have received a copy of the GNU General Public License
 *    along with this program; if not, write to the Free Software
 *    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

/*
 *    RemoveRange.java
 *    Copyright (C) 1999 University of Waikato, Hamilton, New Zealand
 *
 */

package weka.filters.unsupervised.instance;

import weka.core.Capabilities;
import weka.core.Instance;
import weka.core.Instances;
import weka.core.Option;
import weka.core.OptionHandler;
import weka.core.Range;
import weka.core.RevisionUtils;
import weka.core.Utils;
import weka.core.Capabilities.Capability;
import weka.filters.Filter;
import weka.filters.UnsupervisedFilter;

import java.util.Enumeration;
import java.util.Vector;

/**
 * <!-- globalinfo-start --> A filter that removes a given range of instances of
 * a dataset. <p/> <!-- globalinfo-end -->
 * 
 * <!-- options-start --> Valid options are: <p/>
 * 
 * <pre>
 *  -R &lt;inst1,inst2-inst4,...&gt;
 *  Specifies list of instances to select. First and last
 *  are valid indexes. (required)
 * </pre>
 * 
 * <pre>
 *  -V
 *  Specifies if inverse of selection is to be output.
 * </pre>
 * 
 * <!-- options-end -->
 * 
 * @author Eibe Frank (eibe@cs.waikato.ac.nz)
 * @version $Revision: 1.8 $
 */
public class RemoveRange extends Filter implements UnsupervisedFilter,
		OptionHandler {

	/** for serialization */
	static final long serialVersionUID = -3064641215340828695L;

	/** Range of instances requested by the user. */
	private Range m_Range = new Range("first-last");

	/**
	 * Returns an enumeration describing the available options.
	 * 
	 * @return an enumeration of all the available options.
	 */
	public Enumeration listOptions() {

		Vector newVector = new Vector(6);

		newVector.addElement(new Option(
				"\tSpecifies list of instances to select. First and last\n"
						+ "\tare valid indexes. (required)\n", "R", 1,
				"-R <inst1,inst2-inst4,...>"));

		newVector.addElement(new Option(
				"\tSpecifies if inverse of selection is to be output.\n", "V",
				0, "-V"));

		return newVector.elements();
	}

	/**
	 * Parses a given list of options. <p/>
	 * 
	 * <!-- options-start --> Valid options are: <p/>
	 * 
	 * <pre>
	 *  -R &lt;inst1,inst2-inst4,...&gt;
	 *  Specifies list of instances to select. First and last
	 *  are valid indexes. (required)
	 * </pre>
	 * 
	 * <pre>
	 *  -V
	 *  Specifies if inverse of selection is to be output.
	 * </pre>
	 * 
	 * <!-- options-end -->
	 * 
	 * @param options
	 *            the list of options as an array of string.s
	 * @throws Exception
	 *             if an option is not supported.
	 */
	public void setOptions(String[] options) throws Exception {

		String str = Utils.getOption('R', options);
		if (str.length() != 0) {
			setInstancesIndices(str);
		} else {
			setInstancesIndices("first-last");
		}
		setInvertSelection(Utils.getFlag('V', options));

		if (getInputFormat() != null) {
			setInputFormat(getInputFormat());
		}
	}

	/**
	 * Gets the current settings of the filter.
	 * 
	 * @return an array of strings suitable for passing to setOptions.
	 */
	public String[] getOptions() {

		String[] options = new String[8];
		int current = 0;

		if (getInvertSelection()) {
			options[current++] = "-V";
		}
		options[current++] = "-R";
		options[current++] = getInstancesIndices();
		while (current < options.length) {
			options[current++] = "";
		}
		return options;
	}

	/**
	 * Returns a string describing this filter
	 * 
	 * @return a description of the filter suitable for displaying in the GUI.
	 */
	public String globalInfo() {

		return "A filter that removes a given range of instances of a dataset.";
	}

	/**
	 * Returns the tip text for this property
	 * 
	 * @return tip text for this property suitable for displaying in the
	 *         explorer/experimenter gui
	 */
	public String instancesIndicesTipText() {

		return "The range of instances to select. First and last are valid indexes.";
	}

	/**
	 * Gets ranges of instances selected.
	 * 
	 * @return a string containing a comma-separated list of ranges
	 */
	public String getInstancesIndices() {

		return m_Range.getRanges();
	}

	/**
	 * Sets the ranges of instances to be selected. If provided string is null,
	 * ranges won't be used for selecting instances.
	 * 
	 * @param rangeList
	 *            a string representing the list of instances. eg:
	 *            first-3,5,6-last
	 * @throws IllegalArgumentException
	 *             if an invalid range list is supplied
	 */
	public void setInstancesIndices(String rangeList) {

		m_Range.setRanges(rangeList);
	}

	/**
	 * Returns the tip text for this property
	 * 
	 * @return tip text for this property suitable for displaying in the
	 *         explorer/experimenter gui
	 */
	public String invertSelectionTipText() {

		return "Whether to invert the selection.";
	}

	/**
	 * Gets if selection is to be inverted.
	 * 
	 * @return true if the selection is to be inverted
	 */
	public boolean getInvertSelection() {

		return m_Range.getInvert();
	}

	/**
	 * Sets if selection is to be inverted.
	 * 
	 * @param inverse
	 *            true if inversion is to be performed
	 */
	public void setInvertSelection(boolean inverse) {

		m_Range.setInvert(inverse);
	}

	/**
	 * Returns the Capabilities of this filter.
	 * 
	 * @return the capabilities of this object
	 * @see Capabilities
	 */
	public Capabilities getCapabilities() {
		Capabilities result = super.getCapabilities();

		// attributes
		result.enableAllAttributes();
		result.enable(Capability.MISSING_VALUES);

		// class
		result.enableAllClasses();
		result.enable(Capability.MISSING_CLASS_VALUES);
		result.enable(Capability.NO_CLASS);

		return result;
	}

	/**
	 * Sets the format of the input instances.
	 * 
	 * @param instanceInfo
	 *            an Instances object containing the input instance structure
	 *            (any instances contained in the object are ignored - only the
	 *            structure is required).
	 * @return true because outputFormat can be collected immediately
	 * @throws Exception
	 *             if the input format can't be set successfully
	 */
	public boolean setInputFormat(Instances instanceInfo) throws Exception {

		super.setInputFormat(instanceInfo);
		setOutputFormat(instanceInfo);
		return true;
	}

	/**
	 * Input an instance for filtering. Filter requires all training instances
	 * be read before producing output.
	 * 
	 * @param instance
	 *            the input instance
	 * @return true if the filtered instance may now be collected with output().
	 * @throws IllegalStateException
	 *             if no input structure has been defined
	 */
	public boolean input(Instance instance) {

		if (getInputFormat() == null) {
			throw new IllegalStateException("No input instance format defined");
		}
		if (m_NewBatch) {
			resetQueue();
			m_NewBatch = false;
		}
		if (isFirstBatchDone()) {
			push(instance);
			return true;
		} else {
			bufferInput(instance);
			return false;
		}
	}

	/**
	 * Signify that this batch of input to the filter is finished. Output() may
	 * now be called to retrieve the filtered instances.
	 * 
	 * @return true if there are instances pending output
	 * @throws IllegalStateException
	 *             if no input structure has been defined
	 */
	public boolean batchFinished() {

		if (getInputFormat() == null) {
			throw new IllegalStateException("No input instance format defined");
		}

		if (!isFirstBatchDone()) {
			// Push instances for output into output queue
			m_Range.setUpper(getInputFormat().numInstances() - 1);
			for (int i = 0; i < getInputFormat().numInstances(); i++) {
				if (!m_Range.isInRange(i)) {
					push(getInputFormat().instance(i));
				}
			}
		} else {
			for (int i = 0; i < getInputFormat().numInstances(); i++) {
				push(getInputFormat().instance(i));
			}
		}

		flushInput();

		m_NewBatch = true;
		m_FirstBatchDone = true;

		return (numPendingOutput() != 0);
	}

	/**
	 * Returns the revision string.
	 * 
	 * @return the revision
	 */
	public String getRevision() {
		return RevisionUtils.extract("$Revision: 1.8 $");
	}

	/**
	 * Main method for testing this class.
	 * 
	 * @param argv
	 *            should contain arguments to the filter: use -h for help
	 */
	public static void main(String[] argv) {
		runFilter(new RemoveRange(), argv);
	}
}
